Originally Posted by
Tom Campitelli
It is usually the result of rounding the upper back, although more than one thing can cause that. As you grind, there can be a tendency to lift the elbows or to get more horizontal. This can also be coupled with the bar moving forward of the midfoot a little. It happens fairly frequently at limit weights. I have experienced it and it happens on almost all of Feigenbaum's reasonably heavy squats. You are not alone in this. The cues that can potentially help are to keep your shoulder blades pinched back behind you and to try and keep your arms out of the lift. The more you push or pull on the bar with your hands in the squat, the more you run the risk of the bar moving. This should get you started.